Shouldn't such info already be available on the music CD itself?
I think most of us, as consumers, would say yes.
And is it there?
Almost never in my experience. Certainly the software I have used to rip CDs to MP3s never seems to be able to obtain this information from the CD itself. I have read of a few exceptions (notably Sony since 1997).
There are probably several reasons for this, including:
- Music-industry business-model
- The rise of digital distribution
The music industry traditionally made money from the sales of vinyl-records, cassette-tapes and audio-CDs. Protection of their copyright was seen by the industry as essential for their survival. To combat illegal copying of tapes they persuaded legislators to impose a levy on blank tape sales.
The music industry felt that facilitating playback on personal computers was facilitating the infringement of their copyright and thus facilitating their own destruction. So decisions concerning audio-CD contents and formats were heavily skewed against making anything easier for personal computer users.
The audio CD has been established for a long while and there is no point making new CDs incompatible with existing CD-players. This means that care has to be taken if adding digital content to audio-CDs. Digital data and audio data on CDs use completely different and incompatible underlying formatting. This makes it tricky to mix both - though this can be done.
Given a large population of old CD-players, the industry has evidently not seen a benefit to them of "improving" the audio-CD format.
Their perceived use case is: You buy a CD, you put it in a dedicated audio CD-player attached to an audio-amplifier and loudspeakers. You sit down and read the track information printed on the CD cover.
Nowadays the trend is to downloadable content, at least paid-for MP3 files generally contain metadata for artist, album-name, year and genre etc.
It therefore seems unlikely that the music industry has any interest whatsoever in doing anything new with their CD pressing process. Its a dying business after all.
One of the greatest, coolest, but sadly least known and least often used tech things about CDs is "CD-Text."
This has been out for 14 years and I can count on one hand the number of times I've actually SEEN a CD in my car have text associated with it.
From a 2011 blog
Make that nearly 20-years now and no sign of general adoption by the music industry.
Why did CDs originally not incude metadata?
It is worth remembering that the audio-CD was merely a more durable and convenient-sized replacement for the pressed 12" vinyl album disc.
The latter was a purely analogue form with no digital information on it, just the analogue audio waveform in the form of vertical and horizontal undulations
in a continuous spiral groove - with no distinction between tracks other than usually (but not always) a section of silence (no undulations) and wider spacing of the spiral (visible to humans bot not detectable by record-player). Any information about track names etc was present in the printed paper sleevenotes or on the printed cardboard sleeve itself.
So when audio CDs were invented, they took the same approach. They expected CDs to be played in dedicated CD music players, not in computers. Therefore the music was not stored on the CD in the sort of filesystem that a computer would normally use for data files. details of tracks were printed on the paper insert in the plastic CD-case - not placed in the CD contents in any way.
Similarly the audio data on an audio-CD was encoded on a single continuous spiral track. This is very different from the low-level formatting of computer data disks (hard, floppy, CD-data, etc) which typically have a large number of circular tracks arranged concentrically and divided into sectors.
There was no provision for data, probably because this had not been needed for vinyl records and because it would have complicated the manufacture of audio-CD players and made them more expensive at a time when the industry presumably wanted to encourage sales of CDs as a premium, and more profitable, product.
Note that, to identify a CD, programs on PCs have to extract some of the audio data (e.g. the list of song-offsets in the lead-in section of the track or the waveform of part of the first song) and use that as a key for a lookup in a database, typically a remote database elsewhere on the Internet. This is how software retrieves artist-name, album-name, track-name etc.
Some programs do look for CD-Text, sometimes only if they are offline and cannot contact a remote database. So presence of and use of CD-Text is a relative rarity.
There is no computer-readable metadata in most audio-CDs, not even an identifying product number.